1. Field of the Invention
The present invention relates to pressure regulator valves for compressed gas lines and more particularly to pressure regulator valves finding particular but not necessarily exclusive utility for the control of compressed air. More specifically, the present invention relates to a new and improved locking control knob construction for compressed air regulator valves.
2. Description of the Prior Art
Adjustable pressure regulator valves for compressed air lines are ancient and well known in the art. Such valves are conventionally adjusted by a knob or handle by means of which the spring force of the main valve control spring can be varied thereby to vary the pressure output of compressed air from the control valve. For adjusting the spring pressure of the valve spring, there is conventionally provided a valve stem with an appropriate knob.
To prevent inadvertent adjustment of the valve by rotation of the valve stem, it has been the practice to provide a control knob which must be pushed or pulled to engage with the valve stem before the valve stem can be rotated. In its disengaged position the valve control knob can ordinarily be rotated freely without rotating the valve stem.